package cn.micro.eye.commons.utils;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateUtils {

    private static final SimpleDateFormat SDF = new SimpleDateFormat("yyyyMMdd");

    public static String getSerialNum(Long id) {
        return SDF.format(new Date()) + id;
    }

    public static int getAge(Date birthDay) {
        Calendar cal = Calendar.getInstance();
        if (cal.before(birthDay)) {
            throw new IllegalArgumentException("The birthDay is before Now.It's unbelievable!");
        }

        int yearNow = cal.get(Calendar.YEAR);
        int monthNow = cal.get(Calendar.MONTH);
        int dayOfMonthNow = cal.get(Calendar.DAY_OF_MONTH);
        cal.setTime(birthDay);

        int yearBirth = cal.get(Calendar.YEAR);
        int monthBirth = cal.get(Calendar.MONTH);
        int dayOfMonthBirth = cal.get(Calendar.DAY_OF_MONTH);

        int age = yearNow - yearBirth;
        if (monthNow <= monthBirth) {
            if (monthNow == monthBirth) {
                if (dayOfMonthNow < dayOfMonthBirth) {
                    age--;
                }
            } else {
                age--;
            }
        }

        return age;
    }

}
